If you're using Win7, and the system won't recognize more than 136 gB - there's something wrong.
I'd suspect that, most likely, it was a limitation of the system's BIOS or chipset/storage drivers.

But without the detailed specs of the installed drivers on your system, we're reduced to just guessing.

I haven't had an issue with the 137 gB barrier since XP SP1 was released (2002/2003)
As such, I'd expect that there will be other issues with the storage sub-system - so keep an eye out for them!